1. Field of the Invention
The present invention relates to an information managing method, an information managing system, a server apparatus and a recording medium suitable for distributing electronically treatable content data via a recording medium or a network.
2. Description of the Related Art
A system for decrypting data, which is distributed in encryption, by using a decryption key distributed separately has conventionally been proposed, as in Unexamined Japanese Patent Application KOKAI Publication No. 2005-025389. Meanwhile, the applicant has proposed a system for realizing protection on data confidentiality, by recording encrypted data on a recording medium so that the data may be decrypted by a decryption key provided separately, as disclosed in Unexamined Japanese Patent Application KOKAI Publication No. 2006-020253.
Computer programs for performing various processes or content data carrying videos and music in an electronically treatable form are recorded on a recording medium such as, for example, a CD-ROM (Compact Disk Read Only Memory), a DVD-ROM (Digital Versatile Disk Read Only Memory), etc. to be sold or rented. It is also practiced to sell such computer programs and content data via a communication network or rent these via a communication network for a limited rental period or with a limited number of usage chances allowed.
It is often the case that the management of these computer programs and content data is up to the moral of the users who purchased or rented these. Thus, it is the reality that there is no end to some users: committing illegal acts of subletting the programs and data to others without authorization or copying and giving them to others. Software developers and sellers are seriously injured by these illegal acts.
Nevertheless, according to the conventional arts, it is easy to copy, install and reproduce the decrypted data illegally, by storing the decrypted data on other media than the original medium by which the data was distributed. Furthermore, if the decryption key is offered together with the encrypted data, the data can easily be copied, installed and reproduced illegally.